Novel buffer management scheme for CBQ-based IP routers in a combined IntServ and DiffServ architecture

In next-generation IP networks, there will be a mixture of traffic classes with different QoS requirements. Differentiated Services (DiffServ) has evolved from the IETF's earlier Integrated Services (IntServ) standard as a solution to the service quality challenges. In this paper, a novel buffer management scheme called CBQ Priority Buffer Management (CPBM) is presented for IP routers, using the Class Based Queuing (CBQ) scheduler, in a combined IntServ and DiffServ architecture. The objectives of the CPBM scheme are to cope with the various QoS requirements of the IP layer service classes, to utilize the buffer space as efficiently as possible and to successfully coordinate with the CBQ scheduling mechanism in order to improve packet loss performance. The proposed CPBM scheme has been compared with conventional buffer management schemes as Complete Partitioning (CP), Push-Out (PO) and Push-Out with Threshold (POT), using OPNET release 5.1.D as a simulation platform.